1. Field of the Invention
The present invention relates to a method and a system for signalling an aquaplaning condition of a tyre fitted on a vehicle.
2. Description of the Related Art
In the present context, by “aquaplaning” it is intended the condition at which a tyre fully loses its steering property due to the presence of a layer of water interposed between the tyre and the ground (or, more generally; the rolling surface of the tyre) So that, even if the driver of the vehicle on which the tyre is fitted makes attempts to modify the vehicle trajectory, the tyre goes on following the direction substantially dictated by the force of inertia without modifying its trajectory.
The aquaplaning condition occurs when draining and ejection of water in the tread channels and/or grooves, at the footprint area, becomes insufficient, giving rise to loss of grip by the tyre.
Therefore lifting of the tyre from the ground takes place exactly at the footprint area and, as a result, the tyre loses its steering property and traction capability.
The aquaplaning phenomenon can be very dangerous, because under such conditions a driver substantially loses the vehicle control and is no longer able to follow the road, avoid obstacles, etc.
The European patent application EP 1897706 discloses a method and a system for determining the conditions of the ground on which a tyre is rolling.
This document describes a′ solution enabling the vibrations to which the tyre is submitted in the footprint area, the pre-footprint region (“pre-leading domain”) and/or post-footprint region (“post-trailing domain”) to be detected; subsequently, through a map of the prestored values relating the magnitudes derived from the detected vibrations with the ground conditions, it is determined whether the ground is of the type having a “high friction coefficient”, a “medium friction coefficient” or a “low friction coefficient”.
In the same European patent application, still as a function of the detected vibrational signal, it is disclosed that it is also possible to determine whether an agent such as water, snow or ice is interposed between the tyre and the ground.